The portable X-ray fluorescence analyzer (pXRF) allows rapid, economically efficient,
and non-destructive analysis of soil samples and archaeological sediments, providing an
advantage over traditional methods that rely on acid digestion. The pXRF analysis is
based on the detection of secondary (fluorescent) photons excited by X-ray radiation.
The detector distinguishes elements based on photon energy and determines their
concentrations by the number of photons with the same energy. We studied the influence
of different measurement modes (»Soil 60«, »Soil 90«, and »Mining Plus«) and grinding
to a smaller particle size using linear mixed models. We found that the average measured
element concentrations differ based on the measurement mode and particle size fraction.
Larger differences were observed between modes that rely on different calibration
methods. Grinding to a finer particle size usually results in higher measured element
contents, while the differences between repetitions remains mostly unchanged.
Traditional methods based on acid digestion and the pXRF method are not directly
comparable; however, we achieved high similarity with traditional methods for certain
elements. Measurements were conducted in five repetitions, and we observed a
relatively small differences between technical repetitions. Based on statistical analysis
results, we established a measurement procedure and analyzed two series of
archaeological sediment samples from the sites Pungrt near the town of Ig and
Pezdirčeva njiva near Podzemelj, and spatially visualized the results in two different
ways.
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